Electronic remote control system



c. NELSON ELECTRONIC REMOTE CONTROL SYSTEM Nov. 12, 1957 l t e G h S t e e h S 2 Fild May 12, 1952 INVENTOR CARL NELSON PER VIO iiii I Nov. 12, 1957 V c. NELSON 2,813,267

ELECTRONIC REMOTECONTROL SYSTEM Filed May 12, 1952 2 Sheets-Sheet 2 INVENTOR CIIRl mason PER Arrow/5).

United States Patent 2,813,267 ELECTRONIC REMOTE CONTROL SYSTEM Carl Nelson, Toronto, Ontario, Canada, assignor of onefifth to William McKnight, Toronto, Ontario, Canada Application May .12, 1952, Serial No. 287,440

6 Claims. (Cl. 343-225) This invention relates to circuit arrangements for use in connection with signal-controlled supervisory systems.

The invention is particularly adapted for use in connection with the supervision from remote and/ or mobile positions of the conditions of agencies which may require switching operations to respond to a change in a condition at the remote point or points.

It is known to provide at one or more remote points a control signal such, for example, as a radio-frequency carrier wave, some variable characteristic of which is reproduced in amplified form at a terminal station, the variation being used as a control agency to actuate some mechanism. Many of these prior art systems suifer from the disadvantage that they provide at their final output terminals only a low-level of control energy so that extensive use of relay boosters is necessary before any substantial level of control power can be made available.

Such arrangements of the prior art also tend to pro vide very unsatisfactory service in the presence of transient phenomena and where the control signal fails for unplanned reasons no adequate means is provided for suitably indicating non-operation of the control as distinct from some supervisory intelligence of a predetermined code.

It is an object of the present invention to provide a wave-signal-actuated supervisory switching system or arrangement wherein the above mentioned deficiencies are overcome.

It is a further object .of the invention to provide a system of the type indicatedwherein the switching agency is more firmly locked up when the control signal is accompanied'by noise than it is when the noise is absent.

Another object is to provide a system of the kind indicated wherein a minimum number of conventionalcomponents is used to provide power switching of the controlled agency, thisobject being achieved by the electronic triggering of apower storage device of the bucket type.

It will be apparent tothose skilled in the art that these and auxiliary objects of the invention are achieved in accordance with the teachings of the invention by the example ofconstruction to be described, andby similar constructions which lie within the ambit of the appended claims.

The invention in its broad aspect, therefore, comprises a signal-controlled supervisory circuit arrangement including receiver meanstuned to a desired supervisory wave-signal, a local source of oscillations of a frequency different from that of the said supervisory signal, amplifier means for increasing the levels of both the local oscillations and the said: signal in a predetermined ratio, an, electron discharge valve arrangedto operate as a switch, means for applying voltages related to the said amplified oscillation and-the said signal-to provide control voltages, means for applying the said voltage-s to a control electrode of the said electron discharge 'valve to condition its operation, means for determining'thegain of the said amplifier in accordance with a condition of at least one of the amplified signals, and means for adapting the said electron discharge valve to switch the energy contained in a power storage device in order to supervise a specified agency.

In an example of construction which will be later described in full detail, the invention comprises a remote control supervisory circuit arrangement including a remotely positioned intelligence-controlled wave-signal transmitter, means for applying "the transmitted wave to the input of avreceiver tuned to the carrier frequency the said transmitted wave, a twin band amplifier associated therewith and including a plurality of inductivelycoupled electron discharge ,valve networks, a control frequency oscillation generator coupled to an input portion of the said amplifier, a heterodyne frequency generator coupled also to an input portion of the said amplifier, an output wave-separating network selectively coupled to the output of the said twin-band amplifier, means for-selectively rectifying and integrating the respective outputs of the said separator network, means for applying the resultant unidirectional voltages as bias to control the space-current of an electron discharge valve adjusted to function as a switch, means including a grid-controlled electron discharge valve coupled to the said heterodyne frequency generator to provide an additional control signal dependent upon a condition of said generator for controlling the gain of said amplifier, and means 'for adapting the said electron discharge valve switching device to control the energy stored in a power storage agency, for the purpose specified.

The above mentioned example of construction will now .bedescribed in terms of apreferred embodiment and with reference to the accompanying drawings wherein:

Fig. 1 depicts a preferred form of mobile remote supervisory signal transmitter;

"Fig. 2-A depicts one part .of a complete terminalinstalglation circuit diagram comprising a supervisory power-switching arrangement in accordance with the teachings of the invention; and

Fig. 2-13 depicts the remaining part of the said diagram, and A and B figures being taken together.

The specification is addressed to those skilled in the art, and therefore the accompanying drawings will be readily understood .by those familiar with the operation of electronic discharge devices, although certain wellknown details shown therein may not be intimately dealt with in the specification.

Referring now to Figure 1, the remote signal source may be of the portable type employing miniaturized components including triode T1 coupled as an oscillator to provide a master-signal at say, 50 megacycles per second. T2. and T3, wired as shown provide a bufferamplifier-tank circuit which is loaded by antenna screen A1 and antenna tuning capacitor C1. The antenna radiating .element may conveniently take the form of a woven wire tube which contains, within its interior, leads from a battery power-pack. This assembly may be constructed in two parts joined by the antenna-screen/cable A1 and may be readily disposed about the person of a supervising operative.

The transmitter may be provided with .a keying device (not shown) whereby suitable variations may be applied to the .signal according to a predetermined code.

1 The signal from the transmitter is radiated in a predetermined manner and is intercepted by any antenna within itsra-nge, such as aerial A2 (Fig. 2-A).

Figs. 2.A and ,2-B' taken together embrace the whole of a preferred supervisory terminal switching arrangement.

Electron .dischargevalves V1 and V2 together with their assoeiat'edLC and service networks comprise a twinband receiver-amplifier which by suitable adjustment of 9 the LC values in the reactive networks is made capable of simultaneously amplifying the received supervisory signal and the first local source of oscillations. It will be noted that the respective LC networks are arranged in series, in each case, with the respective grid-control elements, and this will be referred to again later.

Since V2 acts as an amplifier and mixer it heterodynes the supervisory incoming signal, amplifies it in terms of its conversion gain and passes a predetermined intermediate signal by way of the appropriate LC network to V3 plus the fundamental first local oscillation by way of its discreet LC networks.

Electron discharge device V4 couples the output of this amplifier to a pair of electron discharge devices V5 and V6 whose input LC networks are so connected that one of the twin-band signals, the H. F. intermediate frequency, appears on the grids of V5 and V6 in phase opposition while the other of the twin-band signals, the lower high frequency first local source of oscillations, appears cophasally upon the said grids, and the output networks of V5 and V6 are arranged to preserve a similar phase relationship so that the output signals, if of predetermined similarity in amplitude at the input of the system, will present a ratio of peak-voltage level which will be a ratio of the push-pull vs. cophasal gain characteristic of the respective LC networks.

The respective signals, now in a set ratio to one another, are split off into two suitably tuned rectifier networks including, respectively, rectifiers D3 and D4, and the outputs of these devices are passed through respective long time-constant integrating networks which provide two predetermined unidirectional output voltages. These will be referred to again later.

Electron discharge valve V9 and its associated networks comprise a first local control frequency generator which is coupled to an injector grid of a multielement valve V of the oscillator-mixer type, and the output of this arrangement is in turn inductively and capacitively coupled by stray field effects to the input stage including V1 of the twin-band amplifier. Signals from V9 will now appear through V10 upon the control grid of V1.

If the frequency of the remote control signal is of the order of 50 megacycles, the separate first local control frequency should be preferably of the order of 200 kilocycles. If an oscillator section of V10 is arranged to operate at 58 megacycles, a heterodyne frequency of the order of 8 megacycles will appear at the grids of V2-V6 whenever a signal from the transmitter is intercepted by A2, and the LC networks of this channel of the twin-band amplifier should be tuned accordingly. The other channel of the twin-band wave translation networks is adjusted to respond to the separate 200 kilocycle control frequency.

It will be now observed that the upper set of LC networks in the twin-band amplifier associated with V2 through V3, V4, V5 and V6 to D4 and D3, are bandpass for the 8 megacycle signal and high-pass for the 200 kilocycle signal, while the lower set of LC networks is band-pass for the 200 kc. signal and low-pass against the 8 megacycle signal. Thus the combined networks associated with valves V3V6 are able to translate efficiently and simultaneously two signals widely separated in frequency, one of them being the local signal from V9 and the other a signal dependent upon conditions at the remote supervisory point.

The rectified and smoothed control voltages from these two signals appear. at points K and S respectively (Fig. Z-B).

Control voltage K stemming from oscillator V9 is constantly available as soon as the equipment is set in operation and unless removed will block-off electron discharge device V7.

It will be obvious to those skilled in the art that having regard to the specific disclosure made in the drawing adjustment of control voltages on V7 and V2 in respect to the developed control voltages from V9 and the antenna can be so modified as to reverse operation characteristics of the controlled supervisory point.

Control signal S stems from the megacycle remote control signal and is picked olf the ratio network at the push-pull level. Signal S will norminally be much higher in level than signal K if both start in at the same order of magnitude. Control signal S, when present, is fed over isolating resistor R1 to the injector grid of V10, and together with the signal from V9 already present on this grid tends to bias off the cathode stream of V10 at this grid-level. The oscillator section of V10 is, however, operating at different points in the cathode-stream and the signal from V10 oscillator will not be greatly aifected. Thus when signal S appears at V10 signals from V9 are cut off from V1, signal K disappears, and V7 isunblocked.

The carrier as seen by the antenna A2 will in most cases be quite low in amplitude and it is a well-known characteristic of wide-band high gain superheterodyne amplifiers that the ENSI and other unwanted parasitics are higher at low signal levels than at zero signal. Noise, therefore, when it accompanies the external control signal, tends to add to the magnitude of signal S but will normally be of insuflicient magnitude to cause interruption of the V9 oscillation (signal K) when there is no external control signal present. It is evident that the present circuit arrangement is virtually noise proof at one position of control and completely noiseproof at the other position.

All arrangements of this kind are subject to possible failure of some valve or component from time to time. -It is evident in the present case that any failure of signal S alone will throw switching valve V7 into the quiescent state. If V10 were to fail as an oscillator the external control signal would not pass through'the amplifier and S would fail. If, however, V9 were to fail at the same time, the signal at K would also fail and V7 would be biased into the active state and freeze in that condition. If V9, only, failed and S remained steady V7 would again freeze in active state. If any of the valves in the amplifier failed, both S and K would disappear and again V7 would freeze inthe active state. V7 being preferably a power valve its failure would in most cases be due to gassy breakdown which would cause V7 to defy its bias controls and, again, freeze in the active state. Therefore, only one likely cause of system failure would throw V7 over into a state of frozen quiescence, namely, a failure of V10 as an oscillator. V8 has been introduced into the system to provide, in association with a detector-integrator network, means for blocking the amplifier and thus causing both S and K to fail if V10 fails. Oscillation from V10 is coupled to a control grid ofvV8 which is connected as an amplifier tuned to the second source of oscillations. It supplies at B (Fig. 2-B) one of two bias voltages which together provide V2 with its grid base. Failure of V10 wipes out one component of the grid base and so depresses the gain of V2 to a point where both S and K fail and cause V7 to now freeze in the active rather than in the quiescent state.

Now, any likely cause of system failure will freeze V7 in the active state so that failures in the terminal equipment are easy to distinguish from failure at the remote point (which would freeze V7 in the other state).

Although it has been stated that V7 is preferably a power valve it is not desirable, in the interests of economy, to employ any large high gain electronic devices in equipment of this type. However, in the field of utility terminals P1, P2, P3 (Fig. 2 B) maybe called upon to handle kilowatts of power necessitating large heavy contacts which place a heavy demand upon the magnetic circuit associated with L2. A low powered V7 would not readily energize such a system, and the adoption of a control relay to power such a contactor from the supgara e??? ply mainsv would": involve considerable reactive: surge efiects thereby. giving rise toirna-intenance problems from.

contact sparking and necessitating. the addition of. costly anti-radio-interferencei: equipment. I

This problem has beeni solved: in: am ingenious manner by adapting the. space: current of V7 to control the discharge cycle of a buckefstorage capacitor, GB of Fig. 2- 3, which: is' charged at a relatively slow rate through limiting 1 resistorrR-2t from the apparatus powerpack.

When V7.' is blockedtrelay magnet LL isnot fiuxed and when S1 and 52' are closed L2? (whichlmay be. a low impedance high energyma-gnetltaactuate. 83:) is fluxed by the heavy current discharge from: CB; When S1 is opened, the bucket capacitonistreleased'from its load, L2 releases and-CB-isrecharged slowly through R2.

The. ratio of. impedance- L2 and resistance R2, expressed in ohms,.mustof course, be:kep,t high, the higher this ratio. is maintained the greater is the: power that can be stored in OB for a givenzrate of cycling.

Itis evident that thesrelay magnets and contacts can be arranged tobe normally openornormally closed in a number of combinationswhich Will readily, occur to those skilled in the art; these can be selected to suit a given application in the, field: of utility..

The exemplificationscontained inthe foregoing paragraphs are not to be. taken-aszlimitingthe scope ofthe invention to the particular forms discussed. The teachings of the. inventionuare to'be construed? imaccordancewith the scopeof theappended'claims.

What I claim is:

1. A signal-controlled supervisory circuit arrangement including receiver means tuned toav desired supervisory high frequency wave-signal, a local: source: of high frequency oscillations of a frequency. diiferent to that of the said supervisory signal, amplifier means for separately increasing the levels of both the local oscillations and the said signalin' a predetermined" ratio, an electron discharge valve arranged to operate asia switch detector, means for deriving voltages from the said amplified oscillation and the said' signal to" provide .control voltages, means forapplying' atleast one of said voltages to a control electrode of the said electron discharge valve to condition its operation, means for determining the gain of the said amplifier in accordance with the magnitude of at least one of the amplified signals and means for adapting the said electron discharge valve to switch the energy contained in a power storage device in response to a change in a said one control voltage.

2. A signal controlled supervisory circuit arrangement comprising receiver means tuned to a desired high frequency supervisory signal, a local high frequency source of oscillations of a frequency greatly diflFerent from that of the said supervisory signal two band, amplifier means capable of simultaneously increasing the levels of both the local oscillations and the said signal independently in a predetermined basic ratio, an electron discharge valve arranged to operate as a switch, means capable of separately acquiring voltages respectively related to the said amplified oscillation and the said signal to provide two unidirectional control voltages, means for applying at least one of the said voltages to a control electrode of the said electron discharge valve to set in a first operative condition, means for determining the gain of the said amplifier in accordance with the magnitude of at least one of the amplified signals and means responsive to the said control voltages for adapting the said electron discharge valve to switch to a second condition when a change occurs in a characteristic of said local oscillation.

3. A signal controlled supervisory circuit arrangement comprising receiver means tuned to a desired high frequency supervisory signal, a first high frequency local source of signal control oscillations having a frequency greatly less than that of the said supervisory signal, a second local source of oscillations of a frequency higher thanthat; of. the said; supervisory signal, amplifier: means capable of simultaneously increasing the levels of the first localoscillation and a. signalrepresenting a difference between the second locally generated oscillation and the said supervisory. signal in tapredetermined basic ratio, an electron discharge valve arrangedto operate as aswitch, means for obtaining control-voltages related to the magnitude of said first local oscillation, and said diiTerencesignal, means for applying. the. said: control voltages as bias to define a firsttconditionofr the said electron discharge valve, meansnresponsive to a control voltage related to a condition of the said second local oscillation for controlling the gain of the. amplifier in accordance with a specified characteristic of. onesaid difference signal, and means responsive to: a change in'a characteristic of said second local sourceiofir oscillations for adapting the said electron discharge: valve. to: switch to a second condition.

4. A signal controlledsupervisory circuit arrangement comprising receiver means tuned. to a desired high frequency supervisory. signal, a first local source of high frequency signal control'oscillations having a-frequency greatly less than that of said supervisory signal, a second local source of oscillations having a frequency diflFerent by a predeterminedsamount' from that of the said supervisorysignal, amplifier means capable of simultaneously increasing in a predetermined. ratio the. levels of the first local control signal oscillation and a signal-representative of adifferencc between the frequency of the second locally generated oscillation and? that of the said supervisory signal, means. includingrectifiers and integrating networks for obtaining two smoot-lrunidirectional control voltages eaclnrelated: in amplitude to an amplitude characteristic of? the first said amplified local oscillation and of said"amplified diflerence-signal, an electron discharge valve network having two stable conditions and connected to operate as a switch, means-for applying the control unidirectional voltage representative of said first local signal control oscillation as biasto a control electrode of said electron dischargevalve network to establish thereinone or. said=stable conditions,-.means for selectively applying the other said control unidirectional volt age to an agency associated with the first source of local signal control oscillations whereby the latter are prevented from generating the corresponding control voltage when the' said other control voltage is present thereby to change the said electron discharge valve network over to its second stable condition bias, means responsive to the absence of a predetermined amplitude characteristic of the second local source of oscillations for blocking the amplifier thereby removing both controlvoltages and setting the electron discharge valve network in its second stable condition, a power storage capacitor, resistive connections for charging said capacitor from a source of unidirectional electric energy, electromagnetic switching means for connecting the said capacitor to a relatively low impedance work circuit, means for utilizing the alternate stable states of the electron discharge valve network to determine the energy condition of the said electromagnetic switching means, and means for utilizing the low impedance work circuit to control the condition of a principal supervising agency.

5. A remote control supervisory circuit arrangementcapable of simultaneously increasing in a predetermined ratio the levels of the first local control signal oscillation and a signal representative of a difference between the frequency of the second locally generated oscillation and that of the said supervisory signal, means including rectifiers and integrating networks for obtaining smooth unidirectional control voltages each related in amplitude to a respective characteristic of the first said amplified local oscillation and of said amplified difference-signal, an electron discharge valve network having two stable conditions and arranged to operate as a switch, means for applying the control voltage representative of said first local signal control oscillation to a control electrode of said electron discharge valve network to establish therein one of said stable conditions, means for applying the other said control voltage to an agency associated with the first source of local signal control oscillations whereby the latter are prevented from reaching the amplifier to generate the corresponding control voltage, thereby to change the said electron discharge valve network over to its second stable condition, means responsive to the absence of a predetermined characteristic of the second local source of oscillations for blocking the amplifier there by removing both control voltages and setting the electron discharge valve network in its second stable condition, a power storage capacitor, resistive connections for charging said capacitor from a source of unidirectional electric energy, electromagnetic switching means for connecting the said capacitor to a relatively low impedance work circuit, means for utilizing the alternate stable states of the electron discharge valve network to determine the energy condition of the said electromagnetic switching means and means for utilizing the low impedance work-circuit to control the condition of a principal supervising agency.

6. A signal controlled supervisory circuit arrangement comprising a receiver means tuned to a desired high frequency supervisory signal, a first local source of high frequency control-signal oscillations having a frequency greatly less than that of the said supervisory signal, a second local source of oscillations having a frequency different from that of the said supervisory signal and coupled thereto to provide a difierence signal, a twin-band amplifier capable of separately but simultaneously amplitying any received wave having the frequency of the said first local control oscillation and the said difference signal, means including rectifiers and integrating networks for obtaining two smoothed unidirectional control voltages each related in magnitude to a specified characteristic of a corresponding said first local oscillation and said difference signal as respectively presented at the output terminations of said amplifier, an electron discharge valve having two stable conditions and arranged to operate as a switch, means for applying one of said smoothed control voltages to a control electrode of said electron discharge valve to establish therein one of the said stable conditions, a control agency connected to determine the amplitude of said first local control oscillation over a range from Zero to a specified maximum, means for applying the second said smoothed voltage to said agency whereby a selected amplitude of said second voltage will prevent the generation of said first control voltage so as to bias the said electron discharge valve over to its second stable condition, means responsive to the absence of a selected characteristic of the second localsource of oscillations for depressing the gain of said amplifier so as to reduce the magnitude of both said smoothed control signals to a level sufiicient to bias the said electron discharge valve over from its first to its second condition, means including a power storage device arranged to alternately store and discharge a specified amount of energy in accordance with changes in the stable states of the said electron discharge device, and

means responsive to receipt of the stored energy for actuating a supervising agency.

References ited in the file of this patent UNITED STATES PATENTS 2,252,811 Lowell Aug. 19, 1941 2,282,972 Koch May 12, 1942 2,316,902 Trevor Apr. 20, 1943 2,339,581 Paulson et al. Jan. 18, 1944 2,457,730 Roberts Dec. 28, 1948 2,501,591 Bach Mar. 21, 1950 2,604,518 Oliver July 22, 1952 

